/*
 * Copyright 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package jane.mvc.utils;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.UndeclaredThrowableException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.regex.Pattern;

import org.junit.Assert;

/**
 * Simple utility class for working with the reflection API and handling
 * reflection exceptions.
 * 
 * <p>
 * Only intended for internal use.
 * 
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @author Rod Johnson
 * @author Costin Leau
 * @author Sam Brannen
 * @author Chris Beams
 * @since 1.2.2
 */
public abstract class ReflectionUtils
{

	private static final Pattern CGLIB_RENAMED_METHOD_PATTERN = Pattern
			.compile("CGLIB\\$(.+)\\$\\d+");

	/**
	 * Attempt to find a {@link Field field} on the supplied {@link Class} with
	 * the supplied <code>name</code>. Searches all superclasses up to
	 * {@link Object}.
	 * 
	 * @param clazz
	 *            the class to introspect
	 * @param name
	 *            the name of the field
	 * @return the corresponding Field object, or <code>null</code> if not found
	 */
	public static Field findField(Class<?> clazz, String name)
	{
		return findField(clazz, name, null);
	}

	/**
	 * Attempt to find a {@link Field field} on the supplied {@link Class} with
	 * the supplied <code>name</code> and/or {@link Class type}. Searches all
	 * superclasses up to {@link Object}.
	 * 
	 * @param clazz
	 *            the class to introspect
	 * @param name
	 *            the name of the field (may be <code>null</code> if type is
	 *            specified)
	 * @param type
	 *            the type of the field (may be <code>null</code> if name is
	 *            specified)
	 * @return the corresponding Field object, or <code>null</code> if not found
	 */
	public static Field findField(Class<?> clazz, String name, Class<?> type)
	{
		Assert.assertNull("Class must not be null", clazz);
		Assert.assertTrue("Either name or type of the field must be specified",
				name != null || type != null);

		Class<?> searchType = clazz;
		while (!Object.class.equals(searchType) && searchType != null)
		{
			Field[] fields = searchType.getDeclaredFields();
			for (Field field : fields)
			{
				if ((name == null || name.equals(field.getName()))
						&& (type == null || type.equals(field.getType())))
				{
					return field;
				}
			}
			searchType = searchType.getSuperclass();
		}
		return null;
	}

	/**
	 * Set the field represented by the supplied {@link Field field object} on
	 * the specified {@link Object target object} to the specified
	 * <code>value</code>. In accordance with {@link Field#set(Object, Object)}
	 * semantics, the new value is automatically unwrapped if the underlying
	 * field has a primitive type.
	 * <p>
	 * Thrown exceptions are handled via a call to
	 * {@link #handleReflectionException(Exception)}.
	 * 
	 * @param field
	 *            the field to set
	 * @param target
	 *            the target object on which to set the field
	 * @param value
	 *            the value to set; may be <code>null</code>
	 */
	public static void setField(Field field, Object target, Object value)
	{
		try
		{
			field.set(target, value);
		} catch (IllegalAccessException ex)
		{
			handleReflectionException(ex);
			throw new IllegalStateException(
					"Unexpected reflection exception - "
							+ ex.getClass().getName() + ": " + ex.getMessage());
		}
	}

	/**
	 * Get the field represented by the supplied {@link Field field object} on
	 * the specified {@link Object target object}. In accordance with
	 * {@link Field#get(Object)} semantics, the returned value is automatically
	 * wrapped if the underlying field has a primitive type.
	 * <p>
	 * Thrown exceptions are handled via a call to
	 * {@link #handleReflectionException(Exception)}.
	 * 
	 * @param field
	 *            the field to get
	 * @param target
	 *            the target object from which to get the field
	 * @return the field's current value
	 */
	public static Object getField(Field field, Object target)
	{
		try
		{
			return field.get(target);
		} catch (IllegalAccessException ex)
		{
			handleReflectionException(ex);
			throw new IllegalStateException(
					"Unexpected reflection exception - "
							+ ex.getClass().getName() + ": " + ex.getMessage());
		}
	}

	/**
	 * Attempt to find a {@link Method} on the supplied class with the supplied
	 * name and no parameters. Searches all superclasses up to
	 * <code>Object</code>.
	 * <p>
	 * Returns <code>null</code> if no {@link Method} can be found.
	 * 
	 * @param clazz
	 *            the class to introspect
	 * @param name
	 *            the name of the method
	 * @return the Method object, or <code>null</code> if none found
	 */
	public static Method findMethod(Class<?> clazz, String name)
	{
		return findMethod(clazz, name, new Class[0]);
	}

	/**
	 * Attempt to find a {@link Method} on the supplied class with the supplied
	 * name and parameter types. Searches all superclasses up to
	 * <code>Object</code>.
	 * <p>
	 * Returns <code>null</code> if no {@link Method} can be found.
	 * 
	 * @param clazz
	 *            the class to introspect
	 * @param name
	 *            the name of the method
	 * @param paramTypes
	 *            the parameter types of the method (may be <code>null</code> to
	 *            indicate any signature)
	 * @return the Method object, or <code>null</code> if none found
	 */
	public static Method findMethod(Class<?> clazz, String name,
			Class<?>... paramTypes)
	{

		Assert.assertNotNull("Class must not be null", clazz);
		Assert.assertNotNull("Method name must not be null", name);

		Class<?> searchType = clazz;
		while (searchType != null)
		{
			Method[] methods = (searchType.isInterface() ? searchType
					.getMethods() : searchType.getDeclaredMethods());
			for (Method method : methods)
			{
				if (name.equals(method.getName())
						&& (paramTypes == null || Arrays.equals(paramTypes,
								method.getParameterTypes())))
				{
					return method;
				}
			}
			searchType = searchType.getSuperclass();
		}
		return null;
	}

	/**
	 * Invoke the specified {@link Method} against the supplied target object
	 * with no arguments. The target object can be <code>null</code> when
	 * invoking a static {@link Method}.
	 * <p>
	 * Thrown exceptions are handled via a call to
	 * {@link #handleReflectionException}.
	 * 
	 * @param method
	 *            the method to invoke
	 * @param target
	 *            the target object to invoke the method on
	 * @return the invocation result, if any
	 * @see #invokeMethod(java.lang.reflect.Method, Object, Object[])
	 */
	public static Object invokeMethod(Method method, Object target)
	{
		return invokeMethod(method, target, new Object[0]);
	}

	/**
	 * Invoke the specified {@link Method} against the supplied target object
	 * with the supplied arguments. The target object can be <code>null</code>
	 * when invoking a static {@link Method}.
	 * <p>
	 * Thrown exceptions are handled via a call to
	 * {@link #handleReflectionException}.
	 * 
	 * @param method
	 *            the method to invoke
	 * @param target
	 *            the target object to invoke the method on
	 * @param args
	 *            the invocation arguments (may be <code>null</code>)
	 * @return the invocation result, if any
	 */
	public static Object invokeMethod(Method method, Object target,
			Object... args)
	{
		try
		{
			return method.invoke(target, args);
		} catch (Exception ex)
		{
			handleReflectionException(ex);
		}
		throw new IllegalStateException("Should never get here");
	}

	/**
	 * Invoke the specified JDBC API {@link Method} against the supplied target
	 * object with no arguments.
	 * 
	 * @param method
	 *            the method to invoke
	 * @param target
	 *            the target object to invoke the method on
	 * @return the invocation result, if any
	 * @throws SQLException
	 *             the JDBC API SQLException to rethrow (if any)
	 * @see #invokeJdbcMethod(java.lang.reflect.Method, Object, Object[])
	 */
	public static Object invokeJdbcMethod(Method method, Object target)
			throws SQLException
	{
		return invokeJdbcMethod(method, target, new Object[0]);
	}

	/**
	 * Invoke the specified JDBC API {@link Method} against the supplied target
	 * object with the supplied arguments.
	 * 
	 * @param method
	 *            the method to invoke
	 * @param target
	 *            the target object to invoke the method on
	 * @param args
	 *            the invocation arguments (may be <code>null</code>)
	 * @return the invocation result, if any
	 * @throws SQLException
	 *             the JDBC API SQLException to rethrow (if any)
	 * @see #invokeMethod(java.lang.reflect.Method, Object, Object[])
	 */
	public static Object invokeJdbcMethod(Method method, Object target,
			Object... args) throws SQLException
	{
		try
		{
			return method.invoke(target, args);
		} catch (IllegalAccessException ex)
		{
			handleReflectionException(ex);
		} catch (InvocationTargetException ex)
		{
			if (ex.getTargetException() instanceof SQLException)
			{
				throw (SQLException) ex.getTargetException();
			}
			handleInvocationTargetException(ex);
		}
		throw new IllegalStateException("Should never get here");
	}

	/**
	 * Handle the given reflection exception. Should only be called if no
	 * checked exception is expected to be thrown by the target method.
	 * <p>
	 * Throws the underlying RuntimeException or Error in case of an
	 * InvocationTargetException with such a root cause. Throws an
	 * IllegalStateException with an appropriate message else.
	 * 
	 * @param ex
	 *            the reflection exception to handle
	 */
	public static void handleReflectionException(Exception ex)
	{
		if (ex instanceof NoSuchMethodException)
		{
			throw new IllegalStateException("Method not found: "
					+ ex.getMessage());
		}
		if (ex instanceof IllegalAccessException)
		{
			throw new IllegalStateException("Could not access method: "
					+ ex.getMessage());
		}
		if (ex instanceof InvocationTargetException)
		{
			handleInvocationTargetException((InvocationTargetException) ex);
		}
		if (ex instanceof RuntimeException)
		{
			throw (RuntimeException) ex;
		}
		throw new UndeclaredThrowableException(ex);
	}

	/**
	 * Handle the given invocation target exception. Should only be called if no
	 * checked exception is expected to be thrown by the target method.
	 * <p>
	 * Throws the underlying RuntimeException or Error in case of such a root
	 * cause. Throws an IllegalStateException else.
	 * 
	 * @param ex
	 *            the invocation target exception to handle
	 */
	public static void handleInvocationTargetException(
			InvocationTargetException ex)
	{
		rethrowRuntimeException(ex.getTargetException());
	}

	/**
	 * Rethrow the given {@link Throwable exception}, which is presumably the
	 * <em>target exception</em> of an {@link InvocationTargetException}. Should
	 * only be called if no checked exception is expected to be thrown by the
	 * target method.
	 * <p>
	 * Rethrows the underlying exception cast to an {@link RuntimeException} or
	 * {@link Error} if appropriate; otherwise, throws an
	 * {@link IllegalStateException}.
	 * 
	 * @param ex
	 *            the exception to rethrow
	 * @throws RuntimeException
	 *             the rethrown exception
	 */
	public static void rethrowRuntimeException(Throwable ex)
	{
		if (ex instanceof RuntimeException)
		{
			throw (RuntimeException) ex;
		}
		if (ex instanceof Error)
		{
			throw (Error) ex;
		}
		throw new UndeclaredThrowableException(ex);
	}

	/**
	 * Rethrow the given {@link Throwable exception}, which is presumably the
	 * <em>target exception</em> of an {@link InvocationTargetException}. Should
	 * only be called if no checked exception is expected to be thrown by the
	 * target method.
	 * <p>
	 * Rethrows the underlying exception cast to an {@link Exception} or
	 * {@link Error} if appropriate; otherwise, throws an
	 * {@link IllegalStateException}.
	 * 
	 * @param ex
	 *            the exception to rethrow
	 * @throws Exception
	 *             the rethrown exception (in case of a checked exception)
	 */
	public static void rethrowException(Throwable ex) throws Exception
	{
		if (ex instanceof Exception)
		{
			throw (Exception) ex;
		}
		if (ex instanceof Error)
		{
			throw (Error) ex;
		}
		throw new UndeclaredThrowableException(ex);
	}

	/**
	 * Determine whether the given method explicitly declares the given
	 * exception or one of its superclasses, which means that an exception of
	 * that type can be propagated as-is within a reflective invocation.
	 * 
	 * @param method
	 *            the declaring method
	 * @param exceptionType
	 *            the exception to throw
	 * @return <code>true</code> if the exception can be thrown as-is;
	 *         <code>false</code> if it needs to be wrapped
	 */
	public static boolean declaresException(Method method,
			Class<?> exceptionType)
	{
		Assert.assertNotNull("Method must not be null", method);

		Class<?>[] declaredExceptions = method.getExceptionTypes();
		for (Class<?> declaredException : declaredExceptions)
		{
			if (declaredException.isAssignableFrom(exceptionType))
			{
				return true;
			}
		}
		return false;
	}

	/**
	 * Determine whether the given field is a "public static final" constant.
	 * 
	 * @param field
	 *            the field to check
	 */
	public static boolean isPublicStaticFinal(Field field)
	{
		int modifiers = field.getModifiers();
		return (Modifier.isPublic(modifiers) && Modifier.isStatic(modifiers) && Modifier
				.isFinal(modifiers));
	}

	/**
	 * Determine whether the given method is an "equals" method.
	 * 
	 * @see java.lang.Object#equals(Object)
	 */
	public static boolean isEqualsMethod(Method method)
	{
		if (method == null || !method.getName().equals("equals"))
		{
			return false;
		}
		Class<?>[] paramTypes = method.getParameterTypes();
		return (paramTypes.length == 1 && paramTypes[0] == Object.class);
	}

	/**
	 * Determine whether the given method is a "hashCode" method.
	 * 
	 * @see java.lang.Object#hashCode()
	 */
	public static boolean isHashCodeMethod(Method method)
	{
		return (method != null && method.getName().equals("hashCode") && method
				.getParameterTypes().length == 0);
	}

	/**
	 * Determine whether the given method is a "toString" method.
	 * 
	 * @see java.lang.Object#toString()
	 */
	public static boolean isToStringMethod(Method method)
	{
		return (method != null && method.getName().equals("toString") && method
				.getParameterTypes().length == 0);
	}

	/**
	 * Determine whether the given method is originally declared by
	 * {@link java.lang.Object}.
	 */
	public static boolean isObjectMethod(Method method)
	{
		try
		{
			Object.class.getDeclaredMethod(method.getName(),
					method.getParameterTypes());
			return true;
		} catch (SecurityException ex)
		{
			return false;
		} catch (NoSuchMethodException ex)
		{
			return false;
		}
	}

	/**
	 * Determine whether the given method is a CGLIB 'renamed' method, following
	 * the pattern "CGLIB$methodName$0".
	 * 
	 * @param renamedMethod
	 *            the method to check
	 * @see net.sf.cglib.proxy.Enhancer#rename
	 */
	public static boolean isCglibRenamedMethod(Method renamedMethod)
	{
		return CGLIB_RENAMED_METHOD_PATTERN.matcher(renamedMethod.getName())
				.matches();
	}

	/**
	 * Make the given field accessible, explicitly setting it accessible if
	 * necessary. The <code>setAccessible(true)</code> method is only called
	 * when actually necessary, to avoid unnecessary conflicts with a JVM
	 * SecurityManager (if active).
	 * 
	 * @param field
	 *            the field to make accessible
	 * @see java.lang.reflect.Field#setAccessible
	 */
	public static void makeAccessible(Field field)
	{
		if ((!Modifier.isPublic(field.getModifiers())
				|| !Modifier.isPublic(field.getDeclaringClass().getModifiers()) || Modifier
					.isFinal(field.getModifiers())) && !field.isAccessible())
		{
			field.setAccessible(true);
		}
	}

	/**
	 * Make the given method accessible, explicitly setting it accessible if
	 * necessary. The <code>setAccessible(true)</code> method is only called
	 * when actually necessary, to avoid unnecessary conflicts with a JVM
	 * SecurityManager (if active).
	 * 
	 * @param method
	 *            the method to make accessible
	 * @see java.lang.reflect.Method#setAccessible
	 */
	public static void makeAccessible(Method method)
	{
		if ((!Modifier.isPublic(method.getModifiers()) || !Modifier
				.isPublic(method.getDeclaringClass().getModifiers()))
				&& !method.isAccessible())
		{
			method.setAccessible(true);
		}
	}

	/**
	 * Make the given constructor accessible, explicitly setting it accessible
	 * if necessary. The <code>setAccessible(true)</code> method is only called
	 * when actually necessary, to avoid unnecessary conflicts with a JVM
	 * SecurityManager (if active).
	 * 
	 * @param ctor
	 *            the constructor to make accessible
	 * @see java.lang.reflect.Constructor#setAccessible
	 */
	public static void makeAccessible(Constructor<?> ctor)
	{
		if ((!Modifier.isPublic(ctor.getModifiers()) || !Modifier.isPublic(ctor
				.getDeclaringClass().getModifiers())) && !ctor.isAccessible())
		{
			ctor.setAccessible(true);
		}
	}

	/**
	 * Perform the given callback operation on all matching methods of the given
	 * class and superclasses.
	 * <p>
	 * The same named method occurring on subclass and superclass will appear
	 * twice, unless excluded by a {@link MethodFilter}.
	 * 
	 * @param clazz
	 *            class to start looking at
	 * @param mc
	 *            the callback to invoke for each method
	 * @see #doWithMethods(Class, MethodCallback, MethodFilter)
	 */
	public static void doWithMethods(Class<?> clazz, MethodCallback mc)
			throws IllegalArgumentException
	{
		doWithMethods(clazz, mc, null);
	}

	/**
	 * Perform the given callback operation on all matching methods of the given
	 * class and superclasses (or given interface and super-interfaces).
	 * <p>
	 * The same named method occurring on subclass and superclass will appear
	 * twice, unless excluded by the specified {@link MethodFilter}.
	 * 
	 * @param clazz
	 *            class to start looking at
	 * @param mc
	 *            the callback to invoke for each method
	 * @param mf
	 *            the filter that determines the methods to apply the callback
	 *            to
	 */
	public static void doWithMethods(Class<?> clazz, MethodCallback mc,
			MethodFilter mf) throws IllegalArgumentException
	{

		// Keep backing up the inheritance hierarchy.
		Method[] methods = clazz.getDeclaredMethods();
		for (Method method : methods)
		{
			if (mf != null && !mf.matches(method))
			{
				continue;
			}
			try
			{
				mc.doWith(method);
			} catch (IllegalAccessException ex)
			{
				throw new IllegalStateException(
						"Shouldn't be illegal to access method '"
								+ method.getName() + "': " + ex);
			}
		}
		if (clazz.getSuperclass() != null)
		{
			doWithMethods(clazz.getSuperclass(), mc, mf);
		} else if (clazz.isInterface())
		{
			for (Class<?> superIfc : clazz.getInterfaces())
			{
				doWithMethods(superIfc, mc, mf);
			}
		}
	}

	/**
	 * Get all declared methods on the leaf class and all superclasses. Leaf
	 * class methods are included first.
	 */
	public static Method[] getAllDeclaredMethods(Class<?> leafClass)
			throws IllegalArgumentException
	{
		final List<Method> methods = new ArrayList<Method>(32);
		doWithMethods(leafClass, new MethodCallback()
		{
			public void doWith(Method method)
			{
				methods.add(method);
			}
		});
		return methods.toArray(new Method[methods.size()]);
	}

	/**
	 * Get the unique set of declared methods on the leaf class and all
	 * superclasses. Leaf class methods are included first and while traversing
	 * the superclass hierarchy any methods found with signatures matching a
	 * method already included are filtered out.
	 */
	public static Method[] getUniqueDeclaredMethods(Class<?> leafClass)
			throws IllegalArgumentException
	{
		final List<Method> methods = new ArrayList<Method>(32);
		doWithMethods(leafClass, new MethodCallback()
		{
			public void doWith(Method method)
			{
				boolean knownSignature = false;
				Method methodBeingOverriddenWithCovariantReturnType = null;

				for (Method existingMethod : methods)
				{
					if (method.getName().equals(existingMethod.getName())
							&& Arrays.equals(method.getParameterTypes(),
									existingMethod.getParameterTypes()))
					{
						// is this a covariant return type situation?
						if (existingMethod.getReturnType() != method
								.getReturnType()
								&& existingMethod.getReturnType()
										.isAssignableFrom(
												method.getReturnType()))
						{
							methodBeingOverriddenWithCovariantReturnType = existingMethod;
						} else
						{
							knownSignature = true;
						}
						break;
					}
				}
				if (methodBeingOverriddenWithCovariantReturnType != null)
				{
					methods.remove(methodBeingOverriddenWithCovariantReturnType);
				}
				if (!knownSignature && !isCglibRenamedMethod(method))
				{
					methods.add(method);
				}
			}
		});
		return methods.toArray(new Method[methods.size()]);
	}

	/**
	 * Invoke the given callback on all fields in the target class, going up the
	 * class hierarchy to get all declared fields.
	 * 
	 * @param clazz
	 *            the target class to analyze
	 * @param fc
	 *            the callback to invoke for each field
	 */
	public static void doWithFields(Class<?> clazz, FieldCallback fc)
			throws IllegalArgumentException
	{
		doWithFields(clazz, fc, null);
	}

	/**
	 * Invoke the given callback on all fields in the target class, going up the
	 * class hierarchy to get all declared fields.
	 * 
	 * @param clazz
	 *            the target class to analyze
	 * @param fc
	 *            the callback to invoke for each field
	 * @param ff
	 *            the filter that determines the fields to apply the callback to
	 */
	public static void doWithFields(Class<?> clazz, FieldCallback fc,
			FieldFilter ff) throws IllegalArgumentException
	{

		// Keep backing up the inheritance hierarchy.
		Class<?> targetClass = clazz;
		do
		{
			Field[] fields = targetClass.getDeclaredFields();
			for (Field field : fields)
			{
				// Skip static and final fields.
				if (ff != null && !ff.matches(field))
				{
					continue;
				}
				try
				{
					fc.doWith(field);
				} catch (IllegalAccessException ex)
				{
					throw new IllegalStateException(
							"Shouldn't be illegal to access field '"
									+ field.getName() + "': " + ex);
				}
			}
			targetClass = targetClass.getSuperclass();
		} while (targetClass != null && targetClass != Object.class);
	}

	/**
	 * Given the source object and the destination, which must be the same class
	 * or a subclass, copy all fields, including inherited fields. Designed to
	 * work on objects with public no-arg constructors.
	 * 
	 * @throws IllegalArgumentException
	 *             if the arguments are incompatible
	 */
	public static void shallowCopyFieldState(final Object src, final Object dest)
			throws IllegalArgumentException
	{
		if (src == null)
		{
			throw new IllegalArgumentException(
					"Source for field copy cannot be null");
		}
		if (dest == null)
		{
			throw new IllegalArgumentException(
					"Destination for field copy cannot be null");
		}
		if (!src.getClass().isAssignableFrom(dest.getClass()))
		{
			throw new IllegalArgumentException("Destination class ["
					+ dest.getClass().getName()
					+ "] must be same or subclass as source class ["
					+ src.getClass().getName() + "]");
		}
		doWithFields(src.getClass(), new FieldCallback()
		{
			public void doWith(Field field) throws IllegalArgumentException,
					IllegalAccessException
			{
				makeAccessible(field);
				Object srcValue = field.get(src);
				field.set(dest, srcValue);
			}
		}, COPYABLE_FIELDS);
	}

	/**
	 * Action to take on each method.
	 */
	public interface MethodCallback
	{

		/**
		 * Perform an operation using the given method.
		 * 
		 * @param method
		 *            the method to operate on
		 */
		void doWith(Method method) throws IllegalArgumentException,
				IllegalAccessException;
	}

	/**
	 * Callback optionally used to filter methods to be operated on by a method
	 * callback.
	 */
	public interface MethodFilter
	{

		/**
		 * Determine whether the given method matches.
		 * 
		 * @param method
		 *            the method to check
		 */
		boolean matches(Method method);
	}

	/**
	 * Callback interface invoked on each field in the hierarchy.
	 */
	public interface FieldCallback
	{

		/**
		 * Perform an operation using the given field.
		 * 
		 * @param field
		 *            the field to operate on
		 */
		void doWith(Field field) throws IllegalArgumentException,
				IllegalAccessException;
	}

	/**
	 * Callback optionally used to filter fields to be operated on by a field
	 * callback.
	 */
	public interface FieldFilter
	{

		/**
		 * Determine whether the given field matches.
		 * 
		 * @param field
		 *            the field to check
		 */
		boolean matches(Field field);
	}

	/**
	 * Pre-built FieldFilter that matches all non-static, non-final fields.
	 */
	public static FieldFilter COPYABLE_FIELDS = new FieldFilter()
	{

		public boolean matches(Field field)
		{
			return !(Modifier.isStatic(field.getModifiers()) || Modifier
					.isFinal(field.getModifiers()));
		}
	};

	/**
	 * Pre-built MethodFilter that matches all non-bridge methods.
	 */
	public static MethodFilter NON_BRIDGED_METHODS = new MethodFilter()
	{

		public boolean matches(Method method)
		{
			return !method.isBridge();
		}
	};

	/**
	 * Pre-built MethodFilter that matches all non-bridge methods which are not
	 * declared on <code>java.lang.Object</code>.
	 */
	public static MethodFilter USER_DECLARED_METHODS = new MethodFilter()
	{

		public boolean matches(Method method)
		{
			return (!method.isBridge() && method.getDeclaringClass() != Object.class);
		}
	};

}